1. Field of the Invention
The present invention generally relates to information processing apparatuses and methods of controlling an access level, and more particularly, to an information processing apparatus and a method of controlling an access level by which it is possible to change an access level in every process.
2. Description of the Related Art
An access allowance area including a device is set for every execution unit of a program such as a task, in a system including a central processing unit (CPU). It is controlled to set the access allowance at a level that is provided for every task. Plural tasks are executed by a manager administrative program. The manager administrative program has a privileged level in which it is allowed to access all areas, in order to manage respective tasks. The CPU makes the manager administrative program execute a change of the task based on an interrupt caused by hardware or software.
According to a related art information processing apparatus, it executes to change a level of the task to the level of the manager administrative program by detecting the interrupt.
However, according to the related art information processing apparatus, if a process to prohibit interrupting to the CPU is implemented, for example, it may be possible to execute the task at the privileged level. Hence, the related art information processing apparatus may have a problem in that it may be possible to alter a program of another task or read out highly secret data such as an encryption key.